Electrochemical reduction of carbon dioxide(ERCD)by renewable energy is a sustainable way to producing valuable chemicals.[1] However,developing high active,selective electrocatalysts are still a huge challenge.[2] Here,we report a series of Co-based macrocyclic compounds with well-defined Co-N4 coordinated centers including phthalocyanine cobalt(CoPc),cobalt(Ⅱ)meso-Tetraphenylporphine(CoTp)and cobalt tetramethoxyphenylporphyrin(CoTop)and explore the relationship between the ligands structure surrounding Co-N4 centers and reaction mechanisms.Electrochemical results show that CoPc possesses higher activity and selectivity for CO relative to those of CoTp and CoTop(Figs.1a and b).Density functional theory calculations(Fig.1c)reveal that CoPc has the rapid formation of key intermediate COOH* and the desorption of CO,demonstrating the crucial role of the ligands structure(phthalocyanine)surrounding Co-N4 in the high CO selectivity.